1. Field
Embodiments of the present invention generally relate to a method and apparatus for plasma processing and, more specifically, to a method and apparatus for plasma processing with improved component parts.
2. Description of the Related Art
The fabrication of microelectronics or integrated circuit devices typically involves a complicated process sequence requiring hundreds of individual steps performed on semiconductors, dielectric and conductive substrates. Examples of these process steps include oxidation, diffusion, ion implantation, thin film deposition, cleaning, etching and lithography. Plasma processes are often used for thin film deposition and etching, which are performed in a plasma chamber. In chemical vapor deposition, reactive species are generated by applying voltages to suitable process gases, and subsequent chemical reactions result in the formation of a thin film on a substrate. In plasma etching, a previously deposited film is exposed to the reactive species in a plasma, often through a patterned mask layer formed in a prior lithography step. Reactions between the reactive species and the deposited film result in the removal, or etching, of the deposited film.
When chamber parts or process kits are exposed to the plasma environment for extended periods, deterioration may occur due to reaction with the plasma species. For example, existing process kits or component parts of a plasma chamber are often made of alumina (aluminum oxide). Halogen-containing gases, e.g., fluorine- or chlorine-containing gases, are used in etching various material layers in circuit fabrication. It is believed that alumina is vulnerable to attack by fluorine species, resulting in the formation of AlxFyOz on the surface of component parts. Such etch by-product may come off as particles during processing, resulting in contamination and defects on the mask substrate. Furthermore, some alumina parts seem to be susceptible to breakage, probably as a result of mechanical stress created during machining. Thus, there is a need for alternative ceramic materials suitable for use as component parts for plasma applications, and for improved processes for fabricating such materials.